Method of testing brakes



Dec. 29, 1931. w, LANGBEIN 1,838,413

METHOD OF TESTING BRAKES Filed May 18, 1927 6 fro/9M5? Patented Dec. 29, 1931 PATENT OFFICE HAROLD W. LANGIBEIN, OF LOS ANGELES, CALIFORNIA METnon or TESTING BRAKES Application filed May 18, 1927. Serial No. 192,272.

g This invention relates to devices for test ing brakes of vehicles such as automobiles, and this application is a continuation iii-part of my applicationentitledBrake testing ma phirge, Serial No. 65,604, filed October 29,

After the brakes of an ,automobilehave been tightened they are tested to determine,

what distance is required to stop the auto-' mobile when it is traveling at a certain speed. At the present time this testing is done on theroad.

It is an object of this inventionto provide a method of testing brakes whereby the distance required to stop the machine which is traveling at a certain-rate of speed by applying the brakes may be determined while the vehicle is stationary. By using my invention it is possible toset the brakes inthe shop, so that the vehicle maybe stopped at La predetermined distance. 7

Another object of the invention is to provide an apparatus for carrying out the abovenoted methods. 7

The invention may be best understood by reference to the accompanying drawings in which:

. Fig. 1 is a plan view of a portion of the apparatus of the invention. f

Fig. 2isa diagram showing the electrical system of the invention. 7 j 1 Fig. 3 is an elevational View of the invention showing its utility. i I I Referring particularly to Fig. 1, the invention provides a drive means having a drive shaft 11 on which members in thefform of drive rollers 12 are secured. The driverollers 12 have outer surfaces whichare concave and are spaced a distanceapart to receive rear wheels 13 of an automobile14. Placed opposite the driverollers 12 are idler rollers 15 mounted on a' shaft 16 which cooperate with the driverollers 12 to support the wheels 13. The drive means isloperated by a power lneanswhich, in this inventiomis' in the form of a motor 18. The motor 18, as illustrated in Fig. 2, is suppli-ed with current-through three-phase wiring 19. which includes amain 5O switch 20. The main switch 20 may be closed by means of an operating button 21. Secured on the drive shaft and forming a part of the drive means is a fly-wheel 23. The flywheel 23 is a momentum member and its func; tlon is to maintain the drive means in rotation even after the motor 18 is deenergized. The fiy-wheel 23 is removable so that for different automobiles being tested, difi'erent sizes o fly-wheels may be used. 7

As shown in Fig. 3 front wheels 25 0f the ,1 vehicle 14 are carried by supporting rollers 60 26. The purpose of the supporting rollers 26 is to align the vehicle 14 so that the axis of the rear wheels 13 is parallel to the axis of the drive shaft 11. i

The rear wheels 13 have brakes 28 which 65 i are operated by a brake lever 29 of the vehicle 14. The brake lever 29 is connected tothe brakes 28 of the wheels 13 by rods 30 as lllllS'. trated in Fig. 3. As shown bestin Figs. 1 H, and 2 a timer 31, including a moving contact Iii 32 and a stationary contact 33, is mounted so that the moving contact 32 is driven by the drive shaft 11. The contacts 32and 33, asillustrated in Fig. 2, are connected in an 7 electric circuit 35. This electric circuit 35 7 is supplied with electricity'by any suitable energy source such as thebattery 36. A con: trolswitch .37 is provided in; the circuit 35, which control switch is connected by a mem- M ber 38 to the brake lever 29. When the brake 30 lever 29 is depressed to operate the brakes 28, the control switch 37 is closed, and when the moving contact 32 of the timer 31 moves into engagement with the stationary contact 33 thereof, the electricity will flo-w through the g5 circuit 35. This circuit 35'includes a magnet 40 which operates an armature 41. The armature 41'is connected by a member 42 to a counter 43. 7 From the drawings'it will be M seen that the magnet 40 will be energized once every time the drive shaft 11 rotates;

consequently the counter will be operated once every revolution of the drive shaft 11. A'circuit 45 is provided whichis connected I, to the circuit 35 in such a manner that ourrent will flow therethrough when the control switch 37 is closed[ Thiscircuit includes a magnet 46 which operatesa bell-crank 47 when it is energized. The bellcrank 47 is I connected by a member 49 to the main switch 0 by manually depressing the button 21. The

drive means is set into rotation by the motor 18 in a direction indicated 'by the arrow 52 of F'g. 3, and the rear wheels 13 of the vehicle are driven by their engagement with the drive rollers 12 in a direction indicated by thearrow 53 of Fig. 3.. hen the wheels are so driven thespeedometer will indicate the rate of speed that the automobile would be traveling ifIit were on the road. W hen a certain predetermined speed is attained, the brake lever is depressed and the brakes 28 are applied. Simultaneously with the applying of the brakes 28,. the control switch 37 is closed. Thecircuits 35 and 45 are instantaneously energized so that the timer 31 is caused to function and the main switch 20 is thrown out so thatthe motor 18 is deenergized. The drive means,. therefore,. is not positively driven by the. motor 18 but is maintained in rotation by inertia or momentum supplied by the heavy fiy-wheel 23. The brakes 28 when applied retard the rotation of. the wheels13, and the wheels 13 place aresistance on the drive rollers 12 which retards the rotationofthe drive means. The timer 31 operates until the drive means is stopped by reason of the applying of the brakes 28. Every revolution of the drive shaft 11 is indicated on the counter 43. The counter 43 may be designed to register the amount of foot travel ofthe wheels 13'required for the stopping ofthem when the brakes 28 are applied 01' may. just register the number or" rotations of the drive shaft 11. If-this is the case, the foot travel of the wheels may be determined by reference to a suitable chart.

When the brakes 28 are applied, there is a tendency for the rear wheels 13 to be slowed with respect to the drive rollers 12. This causes-thedrive rollers .12 to exert a pull on the vehicle 14 in the direction indicated by the'arrow 55 of Fig. 3. My invention provides a means for ascertaining the magnitude of-thispull. Referring. to Fig. 3 a dynamometer', suchas a balance 56, is connected to the vehicle 14'bya member 57 and is also con nected to aistationary part, not shown,.by. a member 53. The pull on the vehicle 14 in the. direction of the arrow 55 is indicated on the dynamometer 56. It isevident that the pull=on the. vehicle 14 is in a certain ratio to the braking pressure of the brakes 28. The

The main.

ratio for each different automobile may be determined and a chart made so that the braking pressure may also be ascertained.

From the foregoing description it will be seen that this invention provides for the testing of the brakes of an automobile in the shop and while the automobile is stationary. This saves considerable time and the method is quite accurate.

The part of the invention which provides for the measuring ofthesbraking pressure is important to the invention.

In: the foregoing description the drive rollers 12 and the fly-wheel 23 are driven by motor18i I-wish it to be understood that an means of driving these parts and the Wheels 13 are within the province of this invention. As an illustration of another drive means the engine of the vehicle 14.n1ay be usedby putting the engine in gear.

I claim as my invention:

1. A method of determining the distance required tostop a vehicle by applying its brakes, which method comprises: rotating the wheels of said vehicle on which the brakes operate by a power drive means capable of storing substantial amounts of kinetic energy; shutting off the power drive means from the wheels; applying said brakes to consume said stored energy; and measuring the movement of said'drive means during the time that said brakes are applied;

2. Armethodof determining the distance required to stop a vehicle by applying its brakes, which method comprises: rotating the wheels of said vehicle on which the brakes operate by a power drive means separate from said vehicle and capable of storing substantial amounts of kinetic energy; shutting ofi' the power drive means from the wheels; applying said brakes to consume said stored energy; and measuring the movement of said drive means during the time that said brakes are applied.

3. A method of determining the distance required to stop a vehicle by applying its brakes comprising: driving the wheels of a vehicle on which the brakes operate by power separate from said vehicle; shutting off the application of said power; applying said brakes; and measuring the movement of the drive meansafter said brakes have been applied;

4. A method of determining the distance required to stop a vehicle by applying its brakes comprising: driving the wheels of a vehicle on which the brakes operate by power separate; from said vehicle; simultaneously shutting ofl'the application of said power and applying said. brakes; and measuring the movement of'the drive means after said brakes have been applied.

5. A method'of testing brakes of a vehicle comprising: placing the wheels ofthe vehicle on'whioh the brakes operate, in driving yso relation with a drive means; supplying power to said drive means so as to drive said wheels; shutting oil the application of said power so that said wheels are driven by the momentum of said drive means; applying said brakes; and measuring the movement of the drive means after said brakes have been applied.

6. A method as presented in claim 5 in which the power is shut off and the brakes applied simultaneously.

7. A method of determining the distance required to stop a vehicle by applying its brakes comprising: rotatingthe wheels of a Vehicle on which the brakes operate; applying said brakes; measuringany rotation of a member bearing against at least one of said Wheels which takes place after said brakes have been applied; and measuring the pull on said vehicle when said brakes are'applied.

8. A method of determining the distance required to stop a vehicle by, applying its brakes comprising: driving the wheels of a vehicle on which the brakes operate by power separate from said vehicle; shutting ofl said power; holding the vehicle against its ten-- dency to move when brakes are applied; applying said brakes measuring the movement of the drive means after said brakes have been applied; and measuring the pull on said vehicle when said brakes are applied.

9. A method of testing brakes of a vehicle comprising: placing the wheels of the vehicle on which the brakes operate, in driving relation with a. drive means; supplying power to said drivemeans so as to drive said wheels; shutting 0E said power so that said wheels are driven by the momentum of said drive means; applying said brakes; measur ing the movement of the drive means after said brakes have been applied; and measuring the pull on said vehicle when said brakes are applied.

10. A brake testing apparatus including: drive means for driving the wheels of the vehicle on which the brakes operate; power means for operating said drive means; shut off means for shutting ofif said power means so that said wheels are driven by the momentum of said drive means; and a dynamometer for measuring the pull on said vehicle by said drive means when said brakes are ap lied.

p 11. brake testing apparatus for vehicles including: a drive means separate from said vehicle and operatively connected to those wheels of the vehicle on which the brakes operate; power means for operating said drive means; and means actuated by the application of said brakes for shutting off said power means so that said wheels are driven by the momentum of said drive means.

12. A brake testing apparatus for vehicles including: a drive means separate from said vehicle and operatively connected to those wheels of the vehicle'on which the brakes drive means during the time that said brakes are applied.

13. A brake testing apparatus for vehicles including: a drive means separate from said vehicle and operatively connected to those wheels of the vehicle on which the brakes operate; power means for operating said drive means; means actuated by the application of said brakes for shutting off said power means so that said wheels are driven by the momentum of said drive means; a counting device; a timer connected to said drive means and adapted to operate said counting device; and means for operatively connecting said timer and said counting de vice when said brakes are actuated.

14. In combination with a vehicle having a pair of wheels equipped with brakes and a lever for actuating said brakes: a drive means for driving said wheels; power means for operating said drive means; a main switch controlling the energiz ation of said power means, said main switch being electrically operated by a control circuit; an auxiliary switch actuated by said lever and electrically connected in said control circuit; a magnetically operated counter; and a timer electrically connected to the magnetic system of said counter and operatively connected to said drive means, said auxiliary switch controlling the time during which said counter is successively energized by said timer.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 14th day of May, 1927.

HAROLD W. LANGBEIN. 

